you have written only half the truth and used words that you or she do not know well the meaning of or use them too lightly without thinking about the consequences that may ensue.
She was part of a group of six who arrived late for class while another group, also of six, arrived on time; we have ascertained that the other group, the one who arrived on time, had NOT booked and had NOT said it while hers had done it.
This situation created confusion and I apologized several times and asked you if you could come the next day.
Faced with your impossibility, I proposed the return of the money or a situation arranged at best or to please everyone.
By choosing to stay, knowing full well how things were, you accepted a contingent and particular situation.
"Bad taste and bitter mouth" what does it mean? Didn't you like my dishes? Did your superfine palate find unwelcome flavors? Was the food too much or too little salty? Too much or too little pepper? Other?
If she found that something was wrong she could tell right away and all the other people would be grateful to her too.
For every self-respecting recipe, as you will find in any cookbook, indicating the cooking time of a dish, the word "about" is coupled to make it clear that some things could cook more or less longer than that indicated. In her lesson we made 5 or 6.
I end by reminding her that I had proposed the return of the money and that accusing me of "wanting her money" seems to me unfair and offensive.
Before writing a sentence, a word, please make sure of its meaning and the consequences that could derive from it.
One last thing: you don't tell half-truths, you tell the truth or a whole lie.